Personally, I wouldn't trust any code written by someone who doesn't even double-check their spelling on their Instructable. You also need instructions on how to execute it, and especially how to exit the program.

Once it's saved as a .bat file, you run it by double clicking it. You end it by closing it like any other window, or if it's in full screen, hitting "Alt" + "Enter" to turn it into a window and then close it like any other window. That code is very safe, I assure you. It's pretty much just the old "Hello World!" programs, but taking advantage of a random number generator.